Summary

Researchers may have found a protein that acts as an elixir of youth, at least in mice. In recent years, researchers studying mice found that giving old animals blood from young ones can reverse some signs of aging, and last year one team identified a growth factor in the blood that they think is partly responsible for the antiaging effect on a specific tissue—the heart. Now that group has shown this same factor can also rejuvenate muscles and the brain. Independently, another team has found that simply injecting plasma from young mice into old mice can boost learning.